RT info:eu-repo/semantics/masterThesis T1 Modal Reduction Principles across Relational Semantics A1 Pinto Prieto, Daira A2 Universidad de Valladolid. Facultad de Filosofía y Letras K1 Correspondence theory K1 Sahlqvist theory K1 Modal logic K1 Many-valued modal logic K1 Modal reduction principles K1 Kripke models K1 Polarity-based semantics K1 Non-distributive logics K1 Teoría de la correspondencia K1 Teoría de Sahlqvist K1 Lógica modal multi-valuada K1 Modelos de Kripke K1 72 Filosofía AB Sahlqvist theory is an important result in the model theory of modal logic, since it identifies a class of formulaswhich have effectively computable first order correspondents. Recently, this theory has been generalisedto a larger set of logics by using their algebraic semantics. This fact has allowed researchers to define inequalitiesof formulas and to determine under which conditions these inequalities have effectively computable firstorder correspondents, that is, under which conditions they are Sahlqvist inequalities. Actually, there are algorithmsthat compute first order correspondents of these inequalities, such as ALBA algorithm. This algorithmtranslates any Sahlqvist inequality to a first order formula, but this translation still strongly depends on semantics.In this thesis, it is proposed a methodology to obtain first order correspondents of certain inequalities,called modal reduction principles, which are easily comparable across two relational semantics: crisp andmany-valued polarity-based semantics. Concretely, this thesis presents an introduction to Sahlqvist theoryand polarity-based semantics and proves that the first order correspondents of modal reduction principles arepure inclusion of binary relations on both semantics. YR 2020 FD 2020 LK http://uvadoc.uva.es/handle/10324/45558 UL http://uvadoc.uva.es/handle/10324/45558 LA eng NO Departamento de Filosofía (Filosofía, Lógica y Filosofía de la Ciencia, Teoría e Historia de la Educación, Filosofía Moral, Estética y Teoría de las Artes) DS UVaDOC RD 06-ago-2024